On Morning Edition moments ago, NPR's Dina Temple-Raston said it isn't known yet whether he may face additional charges.

Abu Ghaith, 48, appeared in a Manhattan federal court. As Dina reported for us Thursday:

"His capture is considered important not just because he was so close to bin Laden but also because U.S. officials have decided to try him in a federal court, not Guantanamo Bay.

"Abu Ghaith may be best known for his multiple appearances in al-Qaida propaganda videos. In one, shortly after 9-11, he is seen sitting next to his father-in-law, the founder of al-Qaida, as he took credit for the Sept. 11 attacks. Then Abu Ghaith took the microphone to praise the attacks as well. ...

"Sources familiar with the case say bin Laden's son-in-law left Iran last month to travel to Turkey. He entered the country under a false passport and Turkish authorities subsequently found him and arrested him in a luxury hotel in Ankara, the Turkish capital. They held him briefly but then decided that they couldn't detain him because hadn't committed a crime on Turkish soil."

Reuters adds that prosecutors said the evidence they have includes videos and audio recordings, and that they expect the trial will last three weeks. A trial date has not yet been set.

The Associated Press reports that prosecutors said Abu Ghaith gave an "extensive statement" to U.S. officials after his arrest.

Update at 2:45 p.m. ET. Suspect Didn't Speak:

Dina tells us that Abu Ghaith "didn't say a word." It was his lawyer who entered the not guilty plea. Prosecutors said Abu Ghaith's statement after his arrest came to 22 pages, she adds.